This invention relates to a live viral vaccine, a method of making the vaccine, and a method of immunizing a host against viruses. More specifically, this invention relates to a live viral vaccine, a method of making the vaccine and a method of immunizing against herpes simplex virus types 1 and 2 (HSV-1 and HSV-2, respectively) using the vaccine. The vaccine incorporates as an effective ingredient at least one intertypic (HSV-1.times.HSV-2) recombinant strain obtained by crossing selected strains of herpes simplex viruses.
Both distinguishable serotypes of herpes simplex virus (designated HSV-1 and HSV-2) cause infection and disease ranging from relatively minor fever blisters on lips to severe genital infections and generalized infections of newborns. Herpes simplex has increasingly been recognized as an etiologic agent in human encephalitis, and may be implicated in some human cancers.
Until now, no effective vaccine against herpes simplex viruses has been known.